shell script challenge regarding background/prompt/pipe

[Graham Cameron_1]

Suspect your program does a close(0) and then opens another fd for reading.

Unless you know which fd this is, or have the patience to keep trying

nohup EXECUTABLE 3nohup EXECUTABLE 4
etc up to 20,

then I'd give up if I were you...

-- Graham

[BIHAN]

mkfifo fifo
nohup EXECUTABLE echo "^M" >fifo

[BIHAN]

missing an & at the end of the nohup line

i think
echo > fifo
would be better than
echo "^M" >fifo

[James Lynch]

Kevin,

How about posting this script so that we can have a look at it?

JL

[Kevin_31]

The real issue is the EXECUTABLE, which is part of Oracle Applications 11i Server, and is over 6 megabytes in size. Probably not the best idea to post (I expect it wouldn't run without the other bits of code that make up the Oracle installation.

Thanks everyone, but I think I'll just have to use cron to restart this bit and keep it out of Omniback post-exec alltogether.

cheers

[Mark Ellzey · Accepted solution]

Kevin,

If you are just trying to answer a prompt that the application requires, and it's a carriage return, I've done it as such:
echo "\013" | APPLICATION > /dev/null 2>&1 &

This works for me in a script that runs an Informix backup procedure, which is normally interactive.

Regards,
Mark

[Kevin_31]

Amazing, I've tried every suggestion listed above, and the last one... finally... worked!

cheers Mark!

(I can always count on ITRC Geniuses)

[Todd McDaniel_1]

No points here...

I just want to say I enjoyed reading this puzzle...

We need more posts like this to test our brains power.

I personally troll the boards to educate myself... and posts like this are helping.

[Ulrich Deiters]

... sorry to be late due to my timezone! A useful trick to communicate with a background process works like this:

1st: You start the background job:
bgjob 2>&1 1>logfile |&

2nd: You retrieve the background job's stderr output (error messages, prompts, etc.):
read -p $bg_output

3rd: You send data to the background job's stdin:
bg_input="some_input"
print -p -R $bg_input

This works with POSIX-compatible shells, e.g., /usr/bin/sh and /usr/bin/ksh, but not with bash.

I hope this is useful for you.